"This kid already has it all figured out. This is definitely not his first go round the cosmic wheel. Say hello to the world Callum Kazee! You certainly know how to make an entrance pal!" Kazee, who is a first-time dad, captioned the shot.

In an interview with People, the actress, who also shares a 6-year-old daughter named Everly with ex-husband Channing Tatum, said having a newborn is easier for her the second time around.

“I’d heard this from a lot of people, that there’s something that happens with the second baby, that there’s a little bit more calm and peace in knowing what’s happening,” she explained. “Knowing what’s coming down the line, you are able to be a little more present and enjoy all of it and it’s so true.”

Dewan also said her fiancé was "incredible" throughout the entire experience.

“It was incredible to watch the awe in his eyes of experiencing birth for the very first time, and the first time he laid eyes on our son,” she said. “He was crying the whole time and he cut the umbilical cord. Seeing his transformation of becoming a dad was one of the best things I’ve ever witnessed. It was beautiful."